medium_ref_batching_windowed_method.java

DataflowPipelineOptions pipelineOptions = PipelineOptionsFactory.fromArgs(args)
    .as(DataflowPipelineOptions.class);
final Pipeline pipeline = org.apache.beam.sdk.Pipeline.create(pipelineOptions);
final String query = "SELECT id, score from [bigquery-public-data:hacker_news.stories]";
Long batchSize = 10L;

pipeline
    .apply("ReadItems", BigQueryIO.readTableRows().fromQuery(query))
    .apply("ParseTableRow", ParDo.of(new ParseTableRow()))
    .apply("Window", Window.into(FixedWindows.of(Duration.standardSeconds(10))))
    .apply("CombineItems", Combine.globally(new ToList<>()))
    .apply("AggregateToBatchOfN", ParDo.of(new AggregateToBatchOfN<>(batchSize)))
    .apply("BatchPredict", ParDo.of(new BatchPredict()))
    .apply("StoreResults", TextIO.write());

pipeline.run();